Bests & Worsts Reviews from Amazon

First off, I did some research and 3400 mAh cells just came out costing about $17-20 EACH... 4000 mAh advertising is clearly false. After going through 5 different sets of Ultrafires from different sources, Its hard to tell for certain which are "real" Ultrafires (I noticed some have printing and/or height differences between them), but ALL of them I recieved are poor after testing. All produced poor flashlight run time and with noticeable differences in time (they'd leave me in the dark randomly while walking my dogs nightly), so I did more research and found that 18650's are very commonly mis-labled knockoffs and/or recycled batteries produced in China, and my problems were far from unique. For more info and a testing and review of many batteries (he seems to have done lots of good work here): www dot lygte hyphen info dot dk you will find actual tests for 2012 of over 4 dozen 18650 batteries. I'd advise against any "Ultrafire" or cheap batteries on Amazon (I've found 100% were much lower mAh than stated and I dont know why they allow this false advertising) and get Protected Panasonic cell batteries such as Orbtronic instead. I purchased 3400mAh Orbtronic protected batteries and tested them against 3000 mAh Ultrafire and another blue "5000mAh" no name cell purchased on Amazon twice and got run time of 1hr 21 and 1hr 23 mins for the Orbtronics vs 32 and 21 mins for the Ultrafires, and 18 and 12 mins run for "5000mAh" batteries in the same LED flashlight. This means you can relatively accurately estimate the BEST "3000 mAh Ultrafire" cells over my purchases to be actually 1350 to 850 mAh (45% to 28% of advertised) and the "5000 mAh" Chinese cells: 740mAh to approx 500mAh! (10% of advertised!) And yes that means the Orbtronics listed as 3400 mAh gave about SIX times more run time and were listed to be only 400 mAh higher. Even if by some miracle there are some "3000 mAh Ultrafires" that actually are what they say, all Ultrafires I test degraded after only one recharge (Orbtronics show no signs of degrading after 3 recharges so far) and not only do the Ultrafires continue to get worse, but its dangerous to keep using Li Ion batteries after they degrade significantly...once they degrade past a certain point they can explode or catch fire... This means that unless you want to buy a volt meter and test your "Ultrafires" before each use to ensure they are in the desirable voltage spectrum of 3.70 to 2.80V/cell (above and below that voltage at a certain point they can explode/catch fire -- research this), you really should buy a good cell such as Panasonic NCR18650B that are Protected (switch off at above and below "safe" voltage limits). Buy the good stuff and ignore the lure of cheap -- its not cheap by comparison for the real capacity, the longevity or the safety issues!